Question

The first term of an arithmetic sequence is 12 and the sum of first 3 term is 54.what is its second term. Write its third term​

Answer 1

Answer:

sn = n/2 [ 2 a + ( n-1) d ]

s3 = 3/2 [ 24 + 2 d]

54 = 3/2 [ 24+2d]

36 = 24+2d

12 = 2d , d = 6

hence , second term = 12+6 = 18

and third term = 18 + 6 = 24.

Answer 2

Answer:

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